title: Results from a multicenter prostate IMRT dosimetry intercomparison for an OCOG-TROG clinical trial.
abstract: OBJECTIVE
  A multi-institution dosimetry intercomparison has been undertaken of prostate intensity modulated radiation therapy (IMRT) delivery. The dosimetry intercomparison was incorporated into the quality assurance for site credentialing for the Trans-Tasman Radiation Oncology Group Prostate Fractionated Irradiation Trial 08.01 clinical trial.
  
  
  METHODS
  An anthropomorphic pelvic phantom with realistic anatomy was used along with multiplanar dosimetry tools for the assessment. Nineteen centers across Australia and New Zealand participated in the study.
  
  
  RESULTS
  In comparing planned versus measured dose to the target at the isocenter within the phantom, all centers were able to achieve a total delivered dose within 3% of planned dose. In multiplanar analysis with radiochromic film using the gamma analysis method to compare delivered and planned dose, pass rates for a 5%/3 mm criterion were better than 90% for a coronal slice through the isocenter. Pass rates for an off-axis coronal slice were also better than 90% except for one instance with 84% pass rate.
  
  
  CONCLUSIONS
  Strengths of the dosimetry assessment procedure included the true anthropomorphic nature of the phantom used, the involvement of an expert from the reference center in carrying out the assessment at every site, and the ability of the assessment to detect and resolve dosimetry discrepancies.
authors.affiliation: Radiation Oncology Queensland, Toowoomba, Queensland 4350, Australia. b.healy@iaea.org
authors.forename: B
authors.initials: B
authors.lastname: Healy
authors.forename: J
authors.initials: J
authors.lastname: Frantzis
authors.forename: R
authors.initials: R
authors.lastname: Murry
authors.forename: J
authors.initials: J
authors.lastname: Martin
authors.forename: A
authors.initials: A
authors.lastname: Plank
authors.forename: M
authors.initials: M
authors.lastname: Middleton
authors.forename: C
authors.initials: C
authors.lastname: Catton
authors.forename: T
authors.initials: T
authors.lastname: Kron
mesh_terms: D003299:Cooperative Behavior; D019583:Dose Fractionation, Radiation; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*